Any Reccomendations???

Hi there,
I am looking into getting a cab. and head, but I havent got any idea at the mo what to look at.
At the minute i still use my old marshall practice combo which has no power at all really, lol, and I use my schools Carlsbro combo for any concerts, but I am leaving school in the next couple of years.
I am a young student bassist, but I have big intentions for when I leave school, so I figured that I need to get something with a bit more umph I play with big bands, concert bands, and will be doing some pit work for concerts etc. so any good all rounder!
I am open for any suggestions, should I look out for a second hand or just get a new one?????

I havent really got a budget lol, as i need to really find out what I am aiming for, I just wanted a few ideas of what you guys suggest I take a look at. Anything really that is good but cheap and cheerful!